Prime number check.
Prime numbers are those numbers which are only divisible by
one and itself.
1,35,7,11,13,17 and so on……..
For small numbers it is easy to say whether number is Prime
number or not.
But for large number like 1189 it is quite difficult to check
its prime number test
But here is the trick that can check Prime number test within
fraction of seconds.
If the number contains 2 or multiple of 2 at ones place it is
not a prime number.
Like 2782, 1322, 1238, 9876 etc.
Whatever is the number use this trick.
Let the number be 89
Divide this number by 8 and then 9, 8+9=17 and 7+1=8
First step = 89/8
not divisible
Second step = 89/9 not divisible
3rd step
= 89/17 not divisible
Final step =89/8
not divisible
So the number is Prime number.
Now check number 139
Important Note If number
contains one at any position doesn’t check the number for one.
First step =139/3
not divisible
Second Step = 139/9
not divisible
Third step = 139/13 not divisible
Final step = 139/4
not divisible.
So the number is Prime number.
Now check the number 453
First step = 453/4
not divisible
Second Step = 453/5 not divisible
Third step = 453/3
= 151.
Since it is divisible so the number is not a Prime number.
This tricks works for a large number also. It will not take
your much time to practice this trick.
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